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Desilicated Kaolin for High Alumina Refractories.
Koch-RK; Traut-DE; Henry-JL
For Reference Only At Bureau Libraries :27 pages
The Bureau of Mines studied, on a limited basis, the preparation of high-alumina refractory-grade material from domestic kaolin clay as a substitute for refractory-grade bauxite. After calcination to remove water of hydration, the crushed clay was desilicated by a naoh-koh aqueous solution leach then dealkalized by a hydrochloric acid wash. Alternative desilication leaches with naoh and koh individually proved less effective. Alternative dealkalization with carbonic acid was also tested but proved unsuccessful. Substantial removal of iron and partial removal of titanium was effected by high- temperature hydrochlorination prior to desilication, but this might prove economically unfeasible. A typical final product after processing contained, in wt pct, 81.5 Al203, 11.2 Si02, 4.6 Tio2, 0.3 Fe2o3, 0.15 K2o, and 0.12 Na2o. Refractory evaluation of this material indicated a pyrometric cone equivalent value of 36 to 37 and a modulus of rupture value of 105 psi at 1,400 deg. C, both values being lower than desired. Further reduction of the titania content was suggested to attain adequate refractory properties.
For Reference Only At Bureau Libraries
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division